Variable-stroke fuel-pump.



0. P. PERSSON.

VARIABLE STROKE FUEL PUMP.

APPLICATION FILED DEC. 30, 1912.

Patented Mar. 16, 1915.

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OTTO F. PERSSON, 0F ERIE, PENNSYLVANIA, ASSIGNOR TO GENERAL ELECTRICCOMPANY, A. CORPORATION OF NEW YORK.

VARIABLE-STROKE FUEL-PUMP.

Specification of Letters Patent.

Patented Mar. 16, 1915.

Application filed December 30, 1912. Serial No. 739,217.

To all whom it may concern:

Be it known that I, om F. PERSSON, a citizen of the United States,residing at Erie, county of Erie, State of Pennsylvania, have inventedcertain new and useful Improvements in Variable-Stroke Fuel-Pumps, ofwhich the following is a specification The present invention relates tovariable stroke fuel pumps for internal combustion engines, and moreespecially for such engines when working on the high compressionconstant pressure plan where the fuel has to be injected into thepulverizers or injectors against the relatively high blast pressureutilized to inject fuel such as crude oil' into the cylinder when thefuel valve is opened.

In such engines the quantity of fuel delivered at each working stroke ofthe pump has to be closely regulated to maintain constant speed of theengine shaft under varying loads. For low engine speeds this problem isrelatively much simpler than for high engine speeds because, in thelatter case, the pumps fail to work properly due to the fact that thetime interval between strokes is so short that the cylinders cannotfill.

I overcome the difficulty above referred to by providing a pump for eachengine cylinder or group of cylinders having two plungers. eachoperating at half the speed which would be required for the ordinarypump under like conditions. The plungers operate in alternation, eachhaving its own suction and discharge valves, a discharge pipe common toboth pumps being provided. The

plungers'are attached to a walking beam actuated by any suitable meanssuch as an eccentric on a reduced speed shaft. In the driving connectionis a sliding block to change the stroke of the plungers whose positionis determined by a speed governor. "he pump is also provided with aby-pass valve on the discharge side which is connected to and actuatedby the starting lever of the engine so to prevent fuel from entering thepulverizer or pulverizers and causing dangerous pressures in thecylinderon the first firing stroke after the starting operation. 1* orsimplicity I have shown only one engine cylinder with its pump but it isto be understood that the arrangement can be duplicated at will, onegoverning means sutlicing for all.

In the accompanying drawing which is illustrative of my invention,Figure 1 shows an internal combustion engine equipped with my improvedpump; Fig. 2 is a vertical section of the pump; and Fig. 3 is a detailedview showing the means for moving the starting valve lever intooperation and the fuel valve lever out of operation.

1 indicates an internal combustion engine of any suitable character; asshown it is provided with two pistons 5 and 6, illustrated in dottedlines, and located in the same cylinder. The engine may have as manycylinders as'is desired.

7 indicates a cam shaft which is driven by the main shaft of the enginethrough suitable power transmitting means. The shaft 7 in addition todriving the cams also drives the vertical shaft 8 of the speed governor9. The weights of the governor are connected to and move the slidingcollar 10 up and down as the speed of the engine changes. Motion fromthe collar is transmitted to the controlling member... of the fuel pumpby the bell-crank lever 11. Situated on one side of the cylinder is afuel injector or pulverizer 12 of any suitable construction which isprovided with a needle valve 13 for controlling the admission of fuel tothe combustion space between the pistons 5 and 6. Located directlyopposite the pulverizer isan air starting valve 14, shown in dottedlines. This is opened by the lever 15 and closed by the spring 16. Thelever 15 is actuated by a link 17 that is connected to. a lever 18, thelatter being mounted on an eccentric carried by the rock shaft 19.

Rigidly secured to the rock shaft is a hand lever 20, by means of whichthe fuel valve can be cut out of operation and the air starting valveinto operation. The lever has three positions, an upright position whenthe engine is running under normal conditions, a horizontal positionwhen the fuel valv'e'is cut out and the air starting valve is inoperation, and a mid-position where both the fuel and 'airstartingvalves arefcut out of operation. As will appear hereinafter,when the lever is ,in the starting and mid-positions a bypass valve inthe fuel pump is open. to bypass fuel from the pulverizer.v The fuelpump comprises a pair of cylinders 25 and 26.. Thesecan with advantagebe formed in the same casting. Each cylinder discharge valve '28. Thesuction valves receive fuel from a chamber 29. The admission of fuel tothis chamber is under the con-- trol of a float 30 and valve 31. Fuel issupplied to the pump from any suitable source by the pipe 32.. Situatedmidway between the cylinders and rising. vertically is a boss 33containing a conduit 34, to which both elements of the pump deliver fuelin alternation. The discharge valves 28 are so arranged that when oneelementof the pump is active no fuel is permitted to pass from it to the.other element.

and 36 indicate the pump plungers which are connected by links 37 to theactuator 38, the latter being made in the .form

, of a walking beam and supported by a pivot 39 carried by the post, orsupport 40. The actuator is provided with a rectangular slot 41, inwhich is-located a sliding block 42. This block is connected to,theeccentric rod 43. Reciprocating motion is imparted to this rod by theeccentric 44, thatis mounted tending arm of the bell-crank lever 11 isconnected by a link 46 to the eccentric rod 43. In this manner theposition of the sliding block 42, which transmits power from the reducedspeed shaft 44 to the pump actuator 38, is adjusted. As the block 42 ismoved to the right the length of. each plunger stroke is decreased, andwhen moved to the left is increased.

During the period that the engine is being started and also whenit isdesired to quickly stop the engine, it is important to prevent fuel frompassing from the pump to the pulverizer. To accomplish this, a by-passvalve 47 is providedas shown in Fig. 2. The valve is provided withacentral port 48, and is so arranged that when in the position shown bothelements of the pump deliver all their fuel to the conduit 34. On theother hand, when the valve is rotated through approximately 90, the fuelinstead of passing through the conduit 34 to the engine, is dischargedthrough the port49 into the supply chamber 29. In order to insure theproper --actuation-of the by-pass valve an'arm 50 is mounted onitsspindle and said arm is connected by the rod 51 to an arm 52 carriedby the rock shaft 19, which is moved by the handle 20. The partsare soarranged that when the handle 20 is in the mid' and horizontalpositions. the by-pass valve 47. is fi sz aand-whenin the uprightposition is c Referring to Fig. 3, 19 indicates the rock shaft andmounted thereon are two eccentrics 53 and 54, the latter being shown indotted lines. Mounted on the eccentric 53 is a lever 55 for actuatingthe fuel valve, and mounted on the eccentric54 is the lever 18- foractuating the air starting valve. These levers are actuated by camscarried on the shaft 7. By moving the-handle 20 the positions of thelevers 55 and 18 are changed, one leverbeing moved into operation withits cam while the otherlever is moved out of operation.

By reason of my improved constructionv the pump can be operated atone-half the speed of the main shaft for a two-cycle en- 'ne and atone-fourth of the engine speed or a four-cycle engine. By thusdecreasing the speed of the pump. ample opportunity is provided for thefuel to flow into the c linders on'the suction strokes and there ore theengine can be operated at very high speed with the certainty that thepumps will operate properly. Reducing the speed of the pump also reducesthe wear thereon and renders it less liable to get out of order. This isof especialiimportance where a num: ber of pumps are driven as a unit,each supplying its own cylinder, since the partial failure of one pump,as by reason of excess leakage, will produce irregularities in theoperation of the engine.*

In accordance with the provisions ofv the patent statutes, I havedescribed the principle of operation of my invention, together with theapparatus which I now consider to represent the best embodiment thereof;but I desire to have it understood that the apparatus shown is onlyillustrative,an'd that the invention canbe carried out by other means.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is.-

1. The combination of an internal combus-J tion engine, a startingmeans, a fuel injector,

a pump having alternately acting plungers,

an actuator common to both, a conduit receiving highpressure fuel fromallof the 'pump plungers and'conveying it 'to' the injector, a by-passvalve in the conduit, means for varying the stroke 'of the pump, and alever for moving the starting means to operative position andsimultaneously therewith moving the by-pass valve to a position where itby-passes fuel from the injector.

2. The combination with an internal combustion engine having an airstarting means,

and a fuel injector, of a fuel pump comprising a pair of cylinders,alternately acting plungers mounted therein, a fuel supply chamber, apivotally supported actuator for the plungers, a shaft'operated by the'engine for driving the actuator, a common discharge ipe for thecylindersconnected to the fue injector, a by-pass connecting thedischarge conduit to said fuel supply chamber, a valve therein, and asingle lever for moving the air starting means to operative position andopening the valve in said bypass.

3. The combination With an internal combustion engine having fueladmission means, of a pump for supplying fuel thereto comprising acasing containing a fuel chamber, a single casting therein carrying apair of cylinders, plunger-s in the cylinders, separate suction anddischarge valves for each cylinder, a common delivery pipe thereforconnected to the fuel admission means, a Walking beam having anelongated slot located on one side of its pivot, links connecting saidbeam to the plungers, a member adapted to slide in said slot, a speedreduction shaft, an eccentric thereon, means connecting the member tothe eccentric for operating the pump plungers, and means for slidingsaid member in said slot to vary the efi ective stroke of the pump.

In witness whereof, I have hereunto set my hand this 26 day of Dec,1912.

OTTO F, PERSSON.

Witnesses:

HERMANN LEMP, L. V. STOELTZLEN.

